Gap Underneath Acrylic Sump

[Harry Muscle]

I'm doing a water test on my new Aqueon Proflex 4 sump on a new stand. This is the first time I've ever dealt with anything acrylic and I wanted to find out how seriously I should be taking gaps underneath the sump. I'm using thin (about 1/16") urethane foam underneath the sump. Here are the pictures of the gaps:

As far as I can tell it's actually the sump that's not perfectly flat not the stand (the sump wasn't square either). Here are pictures of the same spots with straight edges:

Is this a concern I should fix? I've read acrylic expands when in contact with water, so could this gap fix itself maybe? Looking for suggestions on how to proceed (keeping in mind that I want to keep the risk of a leak to a minimum).

Thanks,
Harry

 

[54seaweed]

once it is filled with water it should nest into the foam wouldn't be to concerned so long as its level .

 

[Harry Muscle]

once it is filled with water it should nest into the foam wouldn't be to concerned so long as its level .

Thanks. Actually it's already filled with water in the picture. I'm hoping since acrylic has some give it will settle in in the next day or two but I'm not sure how realistic that is.

Thanks,
Harry

 

[Harry Muscle]

So I took a few more measurements and I think the stand is partly to blame for the gap. That and the sump not being perfectly flat bottomed.

Thanks,
Harry

 

[coralbandit]

Looks OK to me.
My Marineland Model 4 is on sill trim foam for cushion and 3/4 inch plywood for shelf [properly supported through framing].
Over 6 years now at least...